This project provides for the Coordinating Center of the Macular Photocoagulation Study, a multi-center, randomized, controlled, clinical trial. The purpose of the study is to determine whether obliteration of parafoveal neovascular membranes by photocoagulation (argon laser) is of benefit in presumed ocular histoplasmosis and/or senile macular degeneration. Twelve centers through the nation are expected to recruit patients. Recruitment goals are 500 patients in the Histoplasmosis Study and 750 patients in the Senile Macular Degeneration Study.